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Wednesday, February 20, 2013

The Science of Mosh Pits

Parents may never understand their rock 'n' roll loving children, but scientists might. A study published online in arXiv this week seeks to explain the "mosh pit"—using physics.To most scientists, heavy metal refers to elements on the lower end of the periodic table. But to Jesse Silverberg and Matt Bierbaum, doctoral students at Cornell University's department of Condensed Matter Physics, the aggressive music—and the violent dancing that accompanies it—could be a key to understanding extreme situations such as riots and panicked responses to disasters.For the past two years, Silverberg and Bierbaum have studied "moshing," at heavy metal concerts, using theories of collective motion and the physical properties of gasses to better understand the chaos of metal fans' dancing.Moshing, for those who have never attended a heavy metal show, is a form of dancing in which participants bump, jostle, and slam into one another. It's a form of social ritual that anthropologists have likened to spirit possession in its uncontrolled, dynamic, and often violent nature.Silverberg and Bierbaum say it can also be understood by applying models of gaseous particles. As these particles float in groups, they too run, bash, and slam into each other, sending the elements flying in chaotic patterns."We are interested in how humans behave in similar excited states," said Silverberg, "but it's not exactly ethical to start a riot for research."Extreme PhysicsMosh pits provided the scientists with a way to observe excited collective movement without causing undue injury or death. Analyzing hours of recorded footage from concerts and making multiple field trips to music clubs, Silverberg and Bierbaum recognized the particulate physical patterns in the mosh pit.Further, they differentiated two distinct forms of heavy metal dancing: the "mosh pit" itself, which follows the gaseous pattern, and the "circle pit" (where dancers run, smash, and dance in a circular rotation) within it, which adheres to a vortex pattern of particulate behavior.Based on these observations, they created an interactive computer modeldepicting the behavior.Animal Instincts"Herd animals behave in very similar spirit—what physicists call 'flocking' behavior," said Bierbaum. (See "The Genius of Swarms," from the July 2007 issue of National Geographic magazine.)As with groups of flying birds or schooling fish, simple rules can be applied to individuals in large groups—like moshers—to understand what seems to be very complex behavior. This makes modeling possible, allowing computers to re-create immense numbers of actions in a matter of seconds. These models can then be used to design spaces that would minimize trampling or injury, or to tailor responses to disasters like fires."The lessons we've learned in mosh pits [could be used] to build better stadiums, or movie theaters," Silverberg said.James Sethna, one of the researchers' advising professors, hastened to add that his students' forays into heavy metal science "didn't start out for reasons of creating safer stadiums. We did it because it was cool and we wanted to know if we could explain human behavior—albeit slightly intoxicated behavior—without having to use complex [models]."A longtime heavy metal fan himself, Silverberg shared which band produced the best results: "Killswitch Engage ... always gets the crowd nuts. Although of course everyone has their own favorites."